1. Field of the Invention
The present invention relates to compositions comprising sulfoalkyl ether cyclodextrin (“SAE-CD”) compositions, and methods for preparing and using the same.
2. Background of the Invention
Sulfoalkyl ether cyclodextrin (“SAE-CD”) derivatives are polyanionic, hydrophilic, water-soluble cyclodextrins derivatized with sulfoalkyl ether functional groups. An anionic sulfoalkyl ether substituent dramatically improves the aqueous solubility and safety compared to an underivatized cyclodextrin. Reversible, non-covalent, complexation of drugs with sulfoalkyl ether-substituted cyclodextrins generally allows for increased solubility of an active pharmaceutical ingredient and, in some cases, increased stability of drugs in aqueous solutions.
A sulfobutyl ether-β-cyclodextrin having an average degree of substitution of about seven (7) is currently marketed as CAPTISOL® (CyDex Pharmaceuticals, Inc., Lenexa, Kans.). CAPTISOL® has the following chemical structure:
wherein R is (—H)21-n or (—CH2CH2CH2CH2SO3−Na+)n, and n is 6-7.1.
Sulfoalkyl ether-substituted cyclodextrins can be manufactured according to the processes disclosed in, e.g., U.S. Pat. Nos. 5,134,127, 5,376,645 and 6,153,746, which are herein incorporated by reference in their entirety. The SAE-CD derivatives or cyclodextrin derivatives containing a sulfonate functional group can also be made according to Parmerter et al. (U.S. Pat. No. 3,426,011); Gadelle et al. (U.S. Pat. No. 5,578,719); Joullié et al. (U.S. Pat. Nos. 5,760,015 and 5,846,954); Buchanan et al. (U.S. Pat. Nos. 6,610,671 and 6,479,467); Perrier et al. (U.S. Pat. No. 6,524,595); Uchiyama et al. (U.S. Pat. No. 5,512,665); Lammers et al., Recl. Tray. Chim. Pays-Bas 91:733 (1972); Staerke 23:167 (1971); Qu et al., J. Inclusion Phenom. Macro. Chem. 43:213 (2002); Yoshinaga, Japanese Patent No. JP 05001102; U.S. Pat. No. 5,241,059; PCT International Publication No. WO 01/40316, Adam et al., J. Med. Chem. 45:1806 (2002); and Tarver et al., Bioorg. Med. Chem. 10:1819 (2002).
Impurities present in a SAE-CD composition can thus reduce the shelf-life and potency of an active agent composition. Impurities can be removed from a cyclodextrin or SAE-CD composition by exposure to (e.g., mixing with) activated carbon. The treatment of cyclodextrin-containing aqueous solutions and suspensions with activated carbon is known. See, e.g., U.S. Pat. Nos. 4,738,923, 5,393,880 and 5,569,756. However, there is a continued need for SAE-CD compositions with higher purity.